Method of producing yarn



Oct. 2, 1951 H. VON KOHORN METHOD OF PRODUCING YARN Filed llay 17, 1950 INVENTOR HENRY VON KOHQRN ATTORNEYJ Patented Oct. 2, 1951 UNITED STATES PATENT OFFICE The present invention relates to a new and improved method for the production of spun rayon yarn and the novel and improved product resulting therefrom, and it relates more particularly to a new and improved method for the production of spun rayon or tow-to-top method.

In the production of spun rayon yarn, two methods have been generally employed. In the older method and that most widely employed today, the staple fibers which are processed into the spun rayon yarn are produced in a random mixed condition and must be subjected to numerous carding, combing and drawing operations before they can be spun into a suitable yarn.

The above method is obviously highly ineflicient, since the rayon or synthetic fibers are orig inally formed as continuous parallel filaments. Somewhere in the process these filaments are cut and their condition of parallelism destroyed, therefore necessitating subjecting the randomly distributed staple fibers to carding and combing operations in order to reorient them and return them to their original parallel condition so that they may be suitably drawn and spun into a desirable yarn.

In accordance with the second method, which is now being employed to a limited extent, the rayon or other artificial filaments are produced as a bundle of continuous filaments and this bundle is converted to spun rayon yarn without destroying the original condition of parallelism of the filaments. This latter method is referred to as the towto-top or direct spinning process. The filaments may be converted to staple fiber by cutting the filaments forming the original bundle of continuous filaments while maintaining their condition of parallelism so as to form a top. This top is then subjected to numerous drafting operations until a yarn of the desired titre is achieved, and a twist is normally applied to the resulting yarn. In the alternative, the original bundle may be subjected to a draft sufficiently high to stretch the filaments forming the bundle beyond their breaking point so that the bundle is converted from a tow to a. top of staple fibers.

In the event that the starting bundle is of sumciently small titre and the draft sufliciently high to achieve by a single drafting a yarn of the desired thickness or count, this yarn may be directly twisted and packaged. This latter method is usually referred to as direct spinning. However, in

yarn bythe direct spinning 9 Claims. (Cl. 57--157) the event that the tow is of very high titre or the draft is too low, it may be necessary to subject the resulting staple fiber top to further drafting operations in order to achieve a yarn of the desired count. It should be noted that the breaking of the filaments forming the bundle normally occurs only in the first drafting operations, the draft being sufiiciently high to achieve the aforesaid break.

It is with the latter process that the present invention is principally concerned. Where the individual filaments are broken by a drafting operation it is diflicult to control the staple fiber lengths forming the yarn, and these staple fiber lengths have a limited variation. It is highly desirable to increase the range of variation of the staple fiber lengths and thus achieve a yarn of improved characteristics. Furthermore, it is also desirable to produce a yarn by the direct spinning method or by the tow-to-top method, which exhibits the properties of a blended yarn and does not require any blending. This blending is normally impossible or very difiicult to achieve in the aforesaid methods.

Another drawback of the present methods of producing spun rayon yarns by the direct spinning method is that it is difllcult to produce uniform yarns of fine counts. Thus, in order to manufacture spun staple yarns having counts of 40 or finer, it is necessary by the present methods to perform several drafting operations, each of which is relatively low. It is also apparent that the costs of the final yarns are relatively high if a uniform yarn is to be achieved.

It is therefore a principal object of the present invention to provide an improved method for the production of bundles or yarns of staple fiber.

Another object of the present invention is to provide an improved and novel spun rayon yarn.

A further object of the present invention is to provide an improved method of producing spun rayon yarn by the direct spinning process wherein yarns of fine counts may be made having a very high uniformity.

Another object of the present invention is to provide a new and improved method for the production of spun rayon yarns which exhibit the characteristics of blended yarns.

Further objects of the present invention will become apparent from a reading of the following description taken together with the accompanying drawing which illustrates an apparatus 3 by means of which the improved method may be practiced.

The present invention broadly contemplates producing a bundle of continuous filaments, the individual filaments of which .have different elongations, that is, different breaking-point elongations, and subjecting the resulting bundle to a draft suflicient to rupture all the filaments forming said bundle, and thereafter further drafting the resulting bundle of ruptured filaments or directly twisting and packaging the resulting bundle of ruptured filaments.

It is preferred to produce the bundle of continuous filaments with breaking-point elongations ranging from six to twenty per cent, the starting bundle being of such titre and the subsequent draft being sufiiciently high to produce a bundle of staple fibers which may be directly twisted and packaged to produce a yarn of the desired thickness.

Furthermore, the bundle of continuous filaments may be so constituted that a portion of the filaments may be crimped thereby having a relaxed length greater than the corresponding length of the bundle of filaments. Thus, while the breaking-point elongation of the crimped filaments may be approximately twenty per cent or even less, it would be necessary to stretch the bundle containing these filaments an amount much greater than that necessary to stretch corresponding filamentsito the breaking-point elongation since the slack on these filaments must first be taken up. This effectively increases the elongation range necessary to break the filaments forming the, starting bundle.

The resulting yarn produced in accordance with the present method is characterized by a wide range of staple fiber lengths much greater than that normally achieved, and a mixture of fibers having different characteristics such as for dyeing, etc., whereby a blended yarn effectively results.

Reference is now made to the drawing which illustrates an apparatus for practicing the present invention, wherein the artificial filaments are produced by the viscose method although it should be understood that these filaments may be produced by any other well known method.

In the drawing, 2 designates a spinbath trough through which is circulated any well known type of coagulating and regenerating bath such as of the Muller type, and in which is immersed a plurality of multi-apertured spinnerettes, 4, 5, and 6, which are coupled to respective conduits 1. The conduits I, in turn, are connected by way of suitable filters 8, to the outlets of individually driven metering pumps 9. The inlets to the metering pumps 9 are connected to the conduit III, which leads to a source of viscose.

Associated with each of the spinnerettes A, 5, and 6 are corresponding sets of vertically spaced pairs of godets l2, l3, l4, l5, and I6, each of the lower godets II, l3, l5, being provided with thread guides I1, and each of the upper guides l2, I4, l6, likewise being provided with thread guides It, in order to permit applying a multiple wrap of the extruded threads on the corresponding godets so as to minimize slippage. The peripheral speeds of the godets are individually controlled in order to permit the adjustment of the stretch imparted to the threads withdrawn by the respective pairs of godets, and, in addition, to control the denier of the bundles of filaments withdrawn from the respective spinnerettes 4, 5, 4. Furthermore, the metering pumps 9 may likewise be individually adjusted in order to control the titre of the individual groups of filaments forming the final bundle of continuous filaments.

Associated with each three pairs of godets, I IG, is a continuous liquid aftertreating device 20. which is here illustrated as including a thread advancing storage device of the canted cylinder type. Particularly, this liquid aftertreating device consists of a pair of vertically spaced rotating cylindrical drums 2 I, the axes of which are askew relative to each other and do not lie in a common plane.

Disposed above the upper cylinder 2| are one or more liquid spray nozzles, 22, and disposed below the lower cylinder 2| are corresponding catch troughs 23. The necessary treating liquids may thus be sprayed upon the yarn being stored and advanced by the canted cylinders 2| and the spent liquids caught by the trough 23 and either discarded or replenished and recirculated.

The peripheral speed of the cylinders 2| may be adjusted relative to the peripheral speeds of the godets |||6.

Following the liquid aftertreating apparatus 2|! is the drying apparatus 26, which may likewise be formed of a pair of canted cylinders 21, the

canted cylinders 21 preferably being hollow and being provided with suitable means for introducing steam into the interiors thereof and removing the condensed water in order to heat the cylinders. Furthermore, the cylinders 21 are enclosed in a housing 28 and additional heating means 29 may be positioned in the housing 28. Here again, the peripheral speed of the cylinders 21 may be adjusted relative to the peripheral speeds of the cylinders 2| of the aftertreating device 20.

Following each dryer 26 is a driving, twisting and winding apparatus, 30, which consists of a drafting system including the feed rolls I3 and draft rolls 34, the peripheral spe ds of these rolls being individually adjustable, that of the rolls 34 being higher than that of rolls 23.

Furthermore, associated with each of the rolls 33 and 34 are the corresponding thread guides 35 and 36, which are preferably traversed across the rolls in order to prevent the grooving of the corresponding rolls. It has been found that in the present method best results are achieved wherein each of the sets of rolls includes a metal roll and a rubber covered roll urged toward each other by suitable spring or weighted means.

A winding and twisting device is positioned below each of the draft rolls 34 and is here illustrated as being of the ring twisting type and including a rotating spindle 40, which engages a suitable bobbin 4| upon which the spun rayon yarn may be wound. A traverse rail 42 has a circular aperture 43 formed therein which is coaxial with the spindle and which supports a suitable circular track 44 upon which rides the usual ring traveler 46. A suitable means is provided for imparting a traverse motion to the rail 42 relative to the spindle 40 and for suitably varying the traverse of said rail 42 in order to effect the proper build-up of the wound yarn upon the bobbin 4|.

Considering now the operation of the apparatus above described in practicing the present process, viscose is metered to the individual spinnerettes 4, 5, and 5, by means of the corresponding pumps 9, the rate of delivery of the viscose being varied in accordance with the yarn desired. The viscose upon coming in contact with the spinbath which is circulated to trough 2 coagulates into bundles of continuous filaments, and

these in turn are withdrawn by the corresponding godets Ii, l3, and I5, and are then engaged by the corresponding godets II, ,and I6, whose speed are adjustedin order to impart varying degrees of stretch to the corresponding bundles of filaments. Furthermore, suitable plasticizing baths may be fed to the cascade I, so as to permit a greater stretch of the bundles of filaments passing through this plasticizing solution.

The bundles of yarns delivered by the godets II, II. and ii, are thence combined into a single bundle and suitably treated on the aftertreating device 2| in order to effect the substantially complete regeneration, neutralization, desulphurization, and finishing of the bundle of filaments,

whereafter the bundle is fed to the dryer 25.

The dried bundle of continuous filaments may then be packaged in the untwisted or in a slightly twisted condition or ma be directly fed to the drafting equipment 30, wherein a draft at least sufiicient to rupture all of the filaments is imparted to the bundle and the resulting bundle of staple fiber may then be twisted and wound on the bobbin supported on the spindle II. On the other hand, where the dried bundle of continuous filaments is packaged, these may be brought to drafting and twisting and winding -machines where the aforesaid step is accomplished. The latter is preferable, since the linear rate of production of the spun rayon yarn on a single driving, twisting and winding position is generally much less than thelinear rate a pro-- duction of the bundle of continuous filaments.

The speeds of the various advancing elements employed in the production, aftertreating, and drying of the bundle of continuous filaments is adjusted so that the dried bundle of continuous filaments includes filaments having a highrange of breaking-point elongations, said range varying preferably more than 5%. Furthermore, it is preferable that at least one of the groups of filaments forming this dried bundle of continuous filaments be in a crimped state relative to the other groups of filaments so that before these filaments are appreciably stressed, the other filaments must be considerably stretched.

The following is a preferred embodiment of the present process in which the relative peripheral speeds of the various withdrawing and advancing elements are given in order to achieve the desired end product. i The metering pumps 9 may each be driven at equal viscose delivering rates so that the final bundle of continuous filaments contains three groups of filaments of approximately the same total titre. The peripheral speed of the upper godets II, it and i6, and that of the canted cylinders 2! are substantially equal. whereas the canted cylinders 11 of the dryer 25 has a peripheral speed of approximately 4% less than the peripheral speed of the canted cylinders 2 l. The relaxation aiforded the yarn by the decreased peripheral speed of the cylinders 21 increases the range of elongation of the filaments.

Furthermore, the lower godet ii is driven at approximately the same peripheral speed as the upper godet 12: the lower godet is driven at a speed relative to the upper godet ll in order to impart approximately 20% stretch to the filaments transported between these gcdets; and the lower godet I5 is driven at a speed relative to the upper godet 16 so that the corresponding group of filaments has a stretch of approximately 70-75% imparted thereto.

In order to permit the high stretch effected by the godets i5 and ii, a suitable plasticizins,

solution, for example, hot water, is circulated along the cascade I and the group of filaments traveling between the aforesaid godets.

The-three groups of filaments, each having different degrees of stretch imparted thereto, are combined to form a single bundle, andas such transported through the aftertreating stageson the canted cylinders II and are then dried while being transported by the canted cylinders 21. Thereafter the bundle of dried filaments is packaged in an uniwisted state, this package transferred to a suitable long draft spinning mechanism where the filaments are ruptured. and drafted to the the desired titre and the resulting yarn twisted and packaged.- I

The delivery rate of production of the bundle of continuous filaments and the delivery of the viscose to the spinnerets l, 5, and 6, may be so correlated as to produce a final bundle of the desired titre, for example one of 2200 denier, when it is desired to employ this bundle for direct spinning. This bundle may then be subjected to a draft of approximately 15 and the resulting bundle oi staple fibers twisted and wound, the

P spun rayon yarn having a titre of approximately 147 denier.

It should be noted that the range of breakingpoint elongations of the filaments forming the bundle of continuous filaments in the above .example is approximately between 9 and 25%, and this range may be further increased.

In many cases it may be desired to provide a bundle of continuous filaments wherein a'portion of the filaments are in a crimped condition, thereby to increase the necessary effective stretch required to rupture these filaments. This may be achieved by delivering one of the groups of freshly spun filaments in an unstressed crimped condition with the final bundle as it is deposited on the canted cylinders 21 of .the dryer 25 at a linear rate which is greater than the delivery of the remaining filaments. This may be accomplished by increasing the relative speeds of the upper godet I! and the corresponding lower godet ll. Thus, when this bundle of filaments is subjected to a draft, before the breaking-point elongation is reached. which in the case of crimped filaments is high, the crimp must be removed from the filaments thus increasing the efi'ective stretch necessary to rupture those filaments. Thereby the range of staple fiber length in' the final spun rayon yarn is considerably increased.

The resulting yarns produced as set forth above may thereafter be wetted and then dried, thus effecting the shrinkage of the yarn. The staple fibers originating from the filaments of different elongations shrink dliferent amounts, thereby producing a highly novel yarn, which yarn has a high elongation and a very high tenacity. Furthermore, the different staple fibers have different dyeing afilnities, so that upon dyeing the yarn so produced a novel effect is achieved,giving the appearance of a blended yarn.

While there has been described and illlustrated preferred embodiments of the present invention, it is apparent that numerous changes and omissions may be made without departing from the spirit thereof.

This application is a continuation in part of the copending application of Henry Von Kohorn, Serial No. 700.908, filed October 3, 1946, now Patent No. 2,517,946, and entitled Method of Producing Yarn."

What is claimed is:

1. The method of producing a continuous bundle of staple fibers comprising the steps of forming a bundle of continuous filaments, the individual filaments or which have different breaking-point elongations, and subjecting said bundle to a stretch sufilcient to rupture all of said continuous filaments without interrupting the continuity of said bundle, whereby the lengths of the ruptured filaments vary in accordance with the breaking-point elongations oi the corresponding continuous filaments.

tinuity of said bundle, whereby the lengths of the ruptured filaments vary in accordance with the breaking-point elongation and the degree of crimp of the corresponding continuous filaments constituting said bundle.

3. The method of producing a continuous bundle of staple fibers comprising the steps of forming a bundle of continuous filaments, the filaments of which have a range of breakingpoint elongations varying at least and subjecting said bundle to a stretch sufficient to rupture all of said continuous filaments without interrupting the continuity of said bundle, whereby the length of the ruptured filaments vary in accordance with the breaking-point elongations of the corresponding continuous filaments.

4. The method of producing a spun rayon yarn comprising the steps of forming a bundle of continuous filaments. which filaments have break ing-point elongations ranging from 9 to 25%, and subjecting said bundle of continuous filaments to a stretch sufiicient to rupture all of said continuous filaments without interrupting the continuity of said bundle and twisting the resulting bundle of staple fiber to form a spun rayon yarn.

5. The method of producing a staple fiber yarn comprising the steps of forming a bundle of continuous filaments, the individual filaments of which have diilerent breaking-point elongations and a portion of said filaments being in a crimped condition relative to the remaining filaments, subjecting said bundle to a stretch sufiicient to rupture all of said filaments without interrupting the continuity of said bundle, whereby the lengths of the ruptured filaments vary in accordance with the breaking-point elongations and the degree of crimp of the corresponding continuous filaments, and twisting the resulting bundle of staple fibers to form a staple fiber yarn.

6. The method of producing a spun rayon yarn comprising the steps of extruding viscose into a coagulating bath to form a plurality of groups of continuous filaments, subjecting said groups of filaments prior to complete regeneration thereof to difierent degrees of stretch, combining said groups to form a bundle, temporarily storing said bundle while continuously advancing the same and subjecting said advancing bundle to a liquid treatment to effect the purification of said bundle, reducing the linear rate of advance of said bundle, thereby at least partially relaxing the filaments forming said bundle, subjecting said bundle to a drying influence while so relaxed, and subjecting said bundle to a stretch sufiicient to rupture all of said continuous filaments without interrupting the continuity of said bundle. whereby the lengths'oi the ruptured filamentsvary in accordance with the breakingpoint elongations or the corresponding continuous filaments. I

7. The method of producing a spun rayon yarn comprising the step of extruding viscose into a coagulating bath to form a plurality of groups of continuous filaments, subjecting said groups of filaments prior to complete regeneration thereof to different degrees of stretch, combining said groups to form a bundle, temporarily storing said bundle while continuously advancing the same and subjecting said advancing bundle to a liquid aftertreatment to effect the purification of said bundle, reducing the linear rate of advance of said bundle, thereby at least partially relaxing the filaments forming said bundle so that a portion of said filaments are in a crimped condition, subjecting said bundle to a drying infiuence while so relaxed, and subjecting said bundle to a stretch sufiicient to rupture all or said continuou filaments without interrupting the continuity of said bundle, whereby the lengths of the ruptured filaments vary in accordance with the breaking-point elongation oi the corresponding continuous filaments.

8. The method of producing a spun rayon yarn comprising the steps of extruding viscose into a coagulating bath to form a plurality of groups of continuous filaments, subjecting said groups of filaments prior to complete regeneration thereof to different degrees of stretch, combining said groups to form a bundle, temporarily storing said bundle while continuously advancing the same and subjecting said advancing bundle to a liquid treatment to efiect the purification of said bundle, reducing the linear rate of advance of said bundle, thereby at least partially relaxing the filament forming said bundle, subjecting said bundle to a drying influence while so relaxed, subjecting said bundle to a stretch suflicient to rupture all of said continuous filaments without interrupting the continuity of said bundle, whereby the lengths of the ruptured filaments vary in accordance with thebreakingpoint elongation of the corresponding continuous filaments, and wetting and drying the resulting bundle of staple fibers.

9. I The method of producing a spun rayon yarn comprising the steps of extruding viscose into a coagulatingbath to form a plurality of groups of continuous filaments, subjecting said groups of filaments prior to complete regeneration thereof to dififerent degrees of stretch, combining said groups to form a bundle, temporarily storing said bundle while continuously advancing the same and subjecting said advancing bundle in a liquid treatment to eflfect the purification of said bundle, reducing the linear rate of advance of said bundle, thereby at least partially relaxing the filaments forming said bundle, subjecting said bundle to a drying influence while so re laxed, subjecting said bundle to a stretch sum cient to rupture all of said continuous filaments without interrupting the continuity of said bundle, whereby the lengths of the ruptured filaments vary in accordance with the breakingpoint elongation of the corresponding continuous filaments, twisting the resulting bundle of ruptured filaments to form a staple fiber yarn, and wetting and drying said yarn;

HENRY VON KOHORN.

(References on following page) REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Number Number 10 230.476 736,142 859,275

Name Date v Lohrke et al Oct. 18, 1932 Lohrke May 12, 1936 Esselmann et al. May 2, 1939 Bell et a1. Oct. 22, 1940 Kossllnger et al. Nov. 4, 1941 Whitehead Nov. 18, 1941 Hermann Feb. 9, 1943 Name Date Hardy Jan. 7, 1947 Oppenheim Feb. 18, 1947 Bloch Apr. 5, 1949 Robbins, H Aug. 2,- 1949 Von Kohom Aug. 8, 1950 FOREIGN PATENTS Country Date Switzerland Mar. 16, 1944 France Sept. 12, 1932 France June 3, 1940 

